The Carlisle Mosquito Online

Friday, May 7, 2010

Article 28: Carlisle considers “Stretch Code”

Area towns signing up

Should Carlisle adopt a more rigorous building code to boost home energy efficiency? At Annual Town Meeting on May 10, Article 28 will ask voters to adopt the “stretch code,” an optional supplement that raises the requirements on energy efficiency for new homes, additions and major renovations. The stretch code would make home construction and repair more expensive, but would also lower annual heating and cooling costs. What is the net financial impact? Are there other reasons for or against adopting the additional requirements? On April 28, Carlisle’s Energy Task Force hosted a presentation on the new code, assisted by speakers from the Home Energy Star and Green Communities programs.

When Carlisle first began to study it, few if any towns had adopted the stretch code. However, the number of participating communities is growing. Eighteen towns had adopted the stretch code by last week, including Acton, Sudbury, Lincoln, Lexington and Lowell. Concord and Chelmsford approved it on Thursday, April 29.

Energy Task Force member Glenn Reed said that the new code would lower energy use in new homes by 20%. This would cut homeowner energy costs and help reduce greenhouse gas production. He also said it would reduce reliance on foreign energy sources, which would lower the volatility of energy prices. Adoption of the stretch code is also one of five criteria needed to become eligible for the state’s Green Communities grant program.

Last week the majority of the Carlisle Board of Selectmen took a position against adoption of the stretch code. Reasons given include the added cost; that many new homes in town already meet or exceed stretch code targets; and that it would likely add cost to the Benfield Farms affordable housing project (see “Selectmen oppose “stretch code,” April 30).


The school renovation project would be exempt from the stretch code, according to Reed, although he said that the School Building Committee and Energy Task Force are examining options for maximizing the school’s energy efficiency.

Reed said that the engineering has not progressed far enough to determine the exact impact on the Benfield project.

According to the Massachusetts Department of Energy Resources (DOER) the stretch code would add $2,049 to a new 2,672 sq. ft. home construction cost and another $900 for the HERS rater fee, for a total cost of about $3,000. For a home with a 30-year, 6% mortgage, this would increase yearly mortgage expense by $214. However, annual energy costs would be $507 less, compared with the base code in effect after July 1, for a net annual savings of about $300. Under this scenario, it would take ten years to pay for the additional cost of the stretch code home improvements.

Incentives are available for stretch-code homes that participate in the state’s Energy Star Homes program. DOER estimates that in this case, the pay-back period would be closer to five years.

Larger home payback: five - seven years

DOER predicts the stretch code and HERS rater fee would add $6,476 to the construction costs of a 4,462 sq. ft. home. This would add an estimated $471 per year in mortgage costs, while saving $1,455 in annual energy costs, for a net annual saving of $984. In this case, it would take about seven years for the energy savings to pay for the initial expense of meeting the stretch code. Energy Star incentives would shorten the pay-back time to about five years.

Impact in Carlisle: 30 - 60 homes

Building Inspector John Luther said that nine homes are being built in town this year, about the same as last year, but fewer than historical levels (see table). If Carlisle adopts the stretch code, it would affect the 30 to 60 new homes built during the three-year interval before similar requirements are expected to become mandatory statewide.

Building codes evolve

Building codes are typically updated every three years. Energy Star Homes Program Manager Mike Berry described the process. Standards developed by the International Codes Council (ICC) are adopted across the country, with variations provided to account for local conditions. The state is now using the standards published by the ICC in 2006, and will update to ICC-2009 this July. Berry said that construction under the ’09 code will be 10% more energy-efficient than those built according to today’s code. The stretch code is an optional appendix to ICC-2009.

Berry says the stretch code will boost home energy efficiency another 20% beyond ICC-2009 levels. While not finalized, Luther says that the next version will likely include performance goals similar, or identical to the stretch code. This version is expected to be adopted by Massachusetts in 2013.

What’s in the stretch code?

If approved in Carlisle this May, the stretch code would become mandatory on December 31. The code will include different requirements depending on whether the construction is a new home, a renovation or an addition. Commercial renovations would be exempt, as would new commercial construction under 5,000 square feet (sq. ft.).

Standards for new homes

New homes will be required to meet performance standards. Independent rating companies will take measurements and calculate a Home Energy Rating System (HERS) index. A door-blower test will detect the amount of air leakage. Heating and air conditioning ducts will also be tested for leakage. An infra-red camera will inspect the thermal radiation from windows and walls.

Energy Task Force member Dan Cook likens the HERS index to “miles per gallon” for your house. Higher numbers mean greater energy loss from the building. A HERS rating of 0 means the home has a zero net energy loss. According to Berry, homes built under today’s code would typically have a HERS index near 100. Homes built to the upcoming ICC-2009 code will have a HERS index of about 93. Under the stretch code, the HERS requirement for homes under 3,000 square feet would be 70, while the target for larger homes would be 65.

Additions and renovations

There will be “minimal additional impact for most renovation/remodeling work,” according to Energy Task Force member Glenn Reed. Additions and renovations would be allowed to meet new goals through either “prescriptive compliance”, or using a HERS performance target.

Under prescriptive compliance, Reed said that new building elements, such as windows, would have to meet the ICC-2009 energy code and an Energy Star Builders Option Package would be used. Any wall cavities opened during the project would have to be filled with adequate insulation. Only the renovated spaces would be affected by the code. For instance, a project that replaced windows would not trigger new requirements for the home’s heating system. Replacement of broken or storm windows would be exempt.

If the HERS performance standard were used instead, renovations under 2,000 sq. ft. would need a HERS index of 85 or less. Larger renovations would require a HERS index of 80. Berry said performance testing was a good idea for renovations, because the tests can detect small air gaps around insulation, which he said can reduce insulation R-values by 50% or more.

Code compliance

Under the stretch code, the building inspector would perform the usual inspections and in addition would have final authority to approve the independently conducted HERS rating. The question was asked, what would happen if a new home, despite all efforts, had a HERS index of 66, missing the target of 65? Berry answered that, if the builder cannot figure out how to make the house any tighter, then the building inspector has leeway and could grant an Occupancy Permit. He noted that if a special type of door were needed for handicapped accessibility, this would take precedence over the HERS index.

Green Community requirement

“Buildings consume about 40% of the energy in this country. If we can build them right to begin with, then we can pass on better buildings to future generations,” said Joanne Bissetta, the state’s Green Community Coordinator for the Northeast Region. Bissetta spoke about the Green Communities Program and how it relates to the stretch code. She said that the state sets $10 million aside each year to help towns improve energy efficiency. To have access to these funds, towns must qualify as a Green Community. No towns have qualified since the program was created in 2008. However, she expects that between ten and 15 communities will meet the May 14 application deadline and become designated this spring.

Towns must meet five criteria to become Green Communities:

1. Site renewable or alternative energy facilities in town. For example, solar arrays or wind turbines, or a related research and development firm or manufacturing facility.

2. There must be an expedited permitting process for these facilities.

3. Measure an energy baseline for the town and make a plan to cut energy use by 20% in five years. Examples would include reducing energy use in town buildings, fine-tune the timing of traffic lights, etc.

4. Increase energy efficiency of municipal vehicles. Police cruisers, fire trucks and heavy DPW trucks are exempt, she said.

5. Adopt the stretch code.

“How realistic is it that Carlisle can become a Green Community?” asked Larry Bearfield of North Road. He observed that Carlisle has no traffic lights and voters might be reluctant to change the zoning to allow industrial facilities. Reed said, “The stretch code is worthwhile in its own right. Green Communities would be great if it’s possible – it’s the icing on the cake.”

Cook said the task force was looking at possibilities that might work for Carlisle and concluded, “I think we’re making good progress in that direction.” He said that if the town were to qualify, the school has asked about applying for Green Community grants to install solar panels on the school roof.

Bisetta said that she works with towns to help them become designated. She said that about 100 interested towns have received small grants for planning assistance.

Building permits issued


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(Source: Carlisle Annual Reports)

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